Instagram is spurring the biggest shift the fitness world has seen in decades

People who do Kayla Itsines' Bikini Body Guide have created a community online in which they track their progress along the way of their respective journeys.Instagram/Kayla Itsines/stayfitandtravelLog on to Instagram and chances are at least one of your friends has posted a photo of his or her workout regimes or healthy meals. Maybe you're repulsed and disgusted by it.

Consider that part of the process.

A "first reaction [is] to resent how much their friends are posting sweat selfies and ... drinking their shakes," says Carl Daikeler, CEO of at-home workout company Beach Body.

After all, the constant in-your-face nature of wellness is a sharp detour from how things used to be. It was once easy to ignore the need to have a healthy lifestyle; you could just go about your life without constant reminders that you could be healthy.

"However, it has been easy to completely ignore ... an active lifestyle and food choices that would enhance your life," said Daikeler, whose company introduced iconic programs such as Insanity, P90X, and 21-Day Fix to the world.

"It's been so easy to make that optional because it wasn't in your face [before]. Right?" he said. "You go about your life, you've got to do your job, your kids [are] expecting everything of you, but the one thing that was very easy to skip is exercise, and [it was] very easy to justify grabbing pizza because you worked so hard today and your boss yelled at you and you were under so much pressure that you just need a little gratification."

That's not an option anymore.

"However, the rise of Instagram ... and now, Facebook, and now seeing people like you are fitting it into their day and they're putting in the effort and they're enjoying their life and doing things they never thought they could do," Daikeler said.

That could mean sharing a healthy meal that's diet-friendly or sharing post-workout photos.

Autumn Calabrese, the trainer behind the extremely popular 21-Day Fix, also sees the importance of social media.

"For me, coming from being the trainer, I think that it's huge in the fact that it is all about sharing your success or sharing people's success," Calabrese, who shares clients' results on her own Instagram page, said to Business Insider.

It also serves as a new way to show off results — and perhaps more importantly, the process of getting those results, and the process can be the unfortunate part.

"And you can look though these hashtags and not only see people's results, but see what they're doing to get them," she said. "You can see the meal prepping, you can see them sweaty at the ends of their workouts, you can see them on days [when they're] tired on the floor and [are] like '[I] don't wanna do it' [but still] push play [on the DVD]."

It has helped cultivate fitness communities, too — which is extremely important when people are working out at home, in the absence of a visible community that one might find at a gym or a boutique fitness class.

"Social media has kind of made it easier to come together," she said. "I think that they say, 'misery loves company' and — not that it's miserable to work out and — well, maybe it is for some people — but the fact that they have other people to hold them accountable and to say like, 'great job,' 'did you push play?,' way to get those work outs done!,' and they have other people that they can share those results with and other people cheering them on — it sells the product itself."

Further, Calabrese spoke to a positive business implication of social media. "You don't even have to go out and try to market you just have to go and show what it does ... so I've seen amazing things just through like Facebook and through Instagram and [other social media outlets]," she said.

Marketing that comes directly from the customer is arguably more authentic than a commercial. When women see other women share their own journeys (or when a company shares a photo originally posted by someone), it undeniably can intrigue them to want to try that product, too.

Further, Beach Body isn't the only viral workout sensation to take the Internet by storm.

Other brands have profited off of the Instagram community, as well; Kayla Itsines' Bikini Body Guide program, for instance, has cultivated a massive community that goes so far to call itself Kayla's Army, thanks to highly shareable photos and recognizable hashtags on Instagram. In fact, Itsines has arguably built her empire using impressive before-and-after photos, which zero in on her fans' respective journeys.

As Daikeler said, it's just that much harder to ignore wellness these days — but perhaps it's that much easier to find motivation and inspiration.